This study addresses the theoretically under explored question of how fit between project governance configurations, and the knowledge of specialized information technology (IT) and client departments influences information systems development (ISD) performance. It conceptualizes project governance configuration using two classes of project decisions rights-decision control rights and decision management rights. The paper then develops a middle-range theory of how governance-knowledge fit shapes ISD performance by influencing the effective exercise of these decision rights during the development process. Further, the two dimensions of ISD performance - efficiency and effectiveness - are shaped by different classes of project decision rights. Data from 89 projects in 89 firms strongly support the proposed ideas. Implications for theory and practice are also discussed.